umass to /dev/da* mapping
jmc-freebsd2 at milibyte.co.uk
Wed Dec 7 12:51:52 UTC 2011
On Wednesday 07 December 2011, Zane C. B-H. wrote:
> Why are you using a custom Perl script for this instead of the built
> in tools for this?
> Below is how I have it setup on my system...
> In /etc/devfs.rules...
> add path 'da*s*' mode 0660 group 5001
Because devfs only relates to boot time and I want to deal with usb
sticks inserted while the system is running. The allocation of device
numbers is dynamic and depends on what other umass devices are already
connected. Normally my internal memory card reader is allocated da[0-3]
at boot time and the memory stick will appear as da4 when subsequently
inserted but if it's already plugged in when the system boots then it
appears as da0 and the card reader is da[1-4]. If I insert an extra
memory stick it will be allocated the next available device number. I
don't want the user to have to hunt around to determine which device to
mount so my script takes the umass device number supplied by devd and
determines the relevant da* device then it sets the permission to 660
for that device and creates a link, /dev/usbstick, pointing to it. All
the user then has to do is mount /dev/usbstick on his mount point.
Following the earlier tip from Polytropon I now have a working script
which does exactly what I need.
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